New Delhi, Sept. 25 -- With their countries in a generational contest for economic and technological dominance, the two appear to be betting that a combination of personal rapport and mutual interest can prevent the competition from boiling over into open conflict.

"From the time of my first election in 2016, President Xi and I have forged a friendship, a truly great friendship, actually, built on mutual respect and the vital interests of our people," Trump said as he welcomed Xi to the White House for a pomp-filled state visit.

Xi was more pointed than Trump, saying Chinese and American interests are "deeply intertwined" and that the "competition should be a healthy one and should be kept within bounds."

He also reiterated his warning...